Blackthorn blossom without a blackthorn winter?

 The first blackthorn aka sloe Prunus spinosa flowers opened in a hedge alongside one of my favourite walks in Weardale last week. This often signals the start of a 'blackthorn winter', a period of intensely cold north-easterly winds, but this year it looks like we might be lucky - the forecast for the next couple of weeks is for milder weather, warm enough for pollinators to be active. Last spring's blackthorn winter led to pollination failure and a very poor crop of sloes locally, and almost complete crop failure for the damson tree in my garden.

The blackthorn in this length of hedgerow is brutally cut back every winter but this is a tree that produces clusters of flower buds on the old wood that survives, that's almost completely coated in lichens. Blackthorn blossom in a carpet of grey and yellow encrusting lichens is a particularly attractive combination.

Luxuriant growth of a lichen in a hedge in the Tunstall valley

 A leafless hawthorn hedge in the Tunstall valley, County Durham, shorn with geometric precision by a tractor-mounted hedge cutter, but decorated with one of the most luxuriant arrays of lichens I’ve ever seen. Much of the hedge was bare, apart from scattered yellow encrustations of common orange lichen Xanthoria parietina, but short lengths were festooned, like overdressed Christmas trees, with countless dangling fronds of farinose cartilage lichen Ramalina farinacea.

This valley offers high quality lichen habitat, thanks to relatively unpolluted North Pennine winds and humidity from Tunstall reservoir, but why had these short lengths of hedge become so gloriously laden with this particular species? I recalled walking here last summer and finding the same sections defoliated by small ermine moth caterpillars that had sheathed twigs in their silken web. By autumn the hedge had begun to recover, but maybe that leaf-loss and interruption in twig growth had given wind-blown lichen spores sufficient opportunity to colonise bare twigs, trapped by that web of sticky silk? It’s tempting to believe that the beauty of this winter hedgerow was due to the arrival of an egg-laying female ermine moth last spring, a serendipitous event in the endless, unpredictable cycle of life.

Fence post lichen garden

Maybe it's time someone produce a survey of the flora of rotting fence posts. There are so many fascinating and often beautiful examples of these miniature gardens, colonised by mosses, lichens, fungi and flowering plants, where the water retentive end-grain of the wood provides just enough moisture for the organisms to survive throughout the year. 

Pixie-cup lichens Cladonia spp. are some of the commonest colonisers. I noticed this exquisite example on the site of the former Brancepeth colliery at Willington in County Durham.

 

Two late winter/early spring invertebrates

This little crab spider was lurking amongst a bunch of ripening ivy berries. When I disturbed it, the spider quickly disappeared amongst the berries. I posted this picture on Twitter a couple of weeks ago and @ivysuckle kindly identified it for me, as a running crab spider in the genus Philodromus

 There's a shield bug nymph crawling over this lunar landscape of apothecia of the lichen Xanthoria parietina. On Twitter, it was kindly identified for me by @AlanM24217579 as a second instar nymph of the forest bug aka red-legged shieldbug Pentatoma rufipes, apparently the only shieldbug species that overwinters in the nymphal stage.

A Golden Wall

Thursday's Guardian Country Diary is about this remarkable 'golden' wall at Hexham, in Northumberland's Tyne valley. It's a retaining wall beside the main Carlisle to Newcastle railway line, that crosses the Tyne just beyond that bridge in the distance and passes this point at head height.

The golden covering is caused by an alga called Trentepohlia aurea.

It spends the drier months of the year as a  powdery deposit on rocks and tree trunks but when it's wet the alga grows into a forest of minute filaments, forming a dense mat on the surface.

You can see the filaments in this close-up, grouped together to form golden cushions that are a few millimetres in diameter. This wall is constantly wet, due to water percolating through from the railway track bed, so conditions are near-perfect for the growth of the alga.

When the tufts coalesce into a golden carpet they provides a very striking back-drop for other plants that are colonising the wall, like this ivy and .....

The liverwort Conocephalum conicum, also known as snakewort. Its surface is divided into small polygons, each with an air pore at its centre, giving it a resemblance to green snakes' skin.

There are other liverworts on the wetter sections of the wall, including this one which I think is Pellia endiviifolia.

The crevices are home to mosses and this little fern with leathery fronds - wall rue Asplenium ruta-muraria.

The alga seems to thrive particularly well on the cement but there are patches of lichen on some of the stones. A close look at this one revealed ....

.... these fungal fruiting bodies, which look like tiny pink toadstools. I think this is a species in the genus Baeomyces.

Another lichen, this time .....

... with fruiting bodies (apothecia)  that look like minute disks of liquorice. A species of Lecidea?

This lichen is a Cladonia species, probably C. fimbriata

Lichens are formed by the symbiotic association between a fungus and an alga and it's very likely that the algal symbiont of some of the lichens on this wall is Trentepohlia. 

Back now for a closer look at the alga Trentepohlia, this time under the microscope.

Under low magnification (c. x40) with a stereo-microscope you can see the forest of algal filaments that make up those orange cushions, while ....

....... here, under a compound microscope (x100) you can see the cells that make up the filaments, and .....

.... at a higher magnification still (c. x400) you can see the granular, pigmented contents of the cells.

There are animals living in the crevices in this wall, including the fearsome snake-back spider - but that's another story.

A luxuriance of lichens

Today's Guardian Country Diary is about the way in which the right combination of habitat factors - light, humidity and shelter from the wind - can coincide to provide conditions that favour the luxuriant growth of lichens on trees.

All of these lichen species were festooning just three larch trees in a plantation in Hamsterley forest. The trees were at close commercial spacing in neat rows, but only three on the outside row, in a dip in the ground, carried a dense population of lichens. The next row in, about five feet behind, had a few but the row beyond those, that would have been too shaded in summer when the larches carried needles, had none at all.

This beauty, also shown in the four photos immediately below, is (I think) Usnea subfloridana. Its delicate branches don't respond well to being buffeted by gales but in this sheltered location it hung like beards from the trees.

I've yet to identify the following species but they too covered the lower branches of the larches.

Ramalina farinaceae (?)

Hypogymnia physoides (?)

Evernia prunastri (?)

Cetraria chlorophylla (?)

Hypogymnia physoides (?)

Cladonia fimbriata (?) growing on an old larch cone

Lichens

Thursday's Guardian Country Diary explores the wonderful world of lichens that are the brightest objects on moorland in winter. Lichens like .....

...... this delightful Cladonia diversa (?), tipped with what looks like scarlet sealing wax. Those red tips are the apothecia, where microscopic flask-shaped asci shoot their fungal spores out into the breeze. To form another lichen they need to land close enough to the correct alga for the two to form a symbiotic union and develop into a lichen.

This is the moorland described in the Country Diary - a high, windswept path over Birkside Fell above Blanchland, in the Derwent valley on the Durham-Northumberland border. The high rainfall means that nutrients are rapidly leached out of the sandy soil. The area to the right is grouse moor, which from a distance seems like is a sea of dull brown vegetation, until .....

.... you look at what is going on at grouse-eye level, under the canopy of gorse bushes. There, at this time of year, the lichens are at their best and the mosses are actively growing too.

There's a wide range of lichen form and colour. I think this is Cladonia macilenta (?)

..... this looks like Peltigera lactucifolia (?)

.... and this, looking like a forest of tiny golf tees, is Cladonia pyxidata (?)

N.B. the (?) after the specific names mean that these are tentative IDs - I need to check them more carefully to be certain!

Kirkhaugh Church

Today's Guardian Country Diary describes a visit to the unique Kirkhaugh church in the tiny Northumbrian hamlet of Ayle. It's unusual for two reasons: firstly because it is the only church in England dedicated to the Holy Paraclete (the Holy Spirit, symbolised by a dove) rather than to a saint; secondly it has a very unusual needle-sharp spire, the work of the first vicar, who was also the architect of the church. He was Rev. Octavius James, who rebuilt the church on the site of a Mediaeval ruin in 1869, incorporating some of the earlier church's remains but adding a spire like a tooth pick, said to have been inspired by something similar that he saw on his travels in Germany.

Octavius James died in 1889 in a fire in Clarghyll Hall near Alston, another of his architectural enterprises that was a converted 16th. century bastle house.

The interior of the church contains this rather fine marble memorial to a former Lord of the manor, Albany Featherstonehaugh, 'whose line became extinct in 1639'.

The churchyard outside contains this rather melancholy memorial.....

..... with a fine encrustation of lichens, while over against the churchyard wall ....

....... this headstone, whose inscription has been worn away by the Northumbrian weather, has been split in two by the trunk of a horse chestnut that must have been planted as a sapling too close to the grave, perhaps a century ago.

The horse chestnut, which seems to be perfectly healthy, is gradually engulfing the headstone.

Many of the old headstones are well worn and barely decipherable, but host a range of lichens that would probably keep a lichenologist amused for quite some time..

The most delightful inscription in the graveyard is this one, on the back of a headstone whose main inscription has been erased by weather and lichens. The epitaph describes the grave's anonymous occupant as:

A loyal Subject in his Life
A Good Husband to his Wife
A Father to his Children Dear
A Good Neighbour Lieth Here